... guarantee.2.We can match the different rubber ring according to the different medium conditions, such as NBR ,PTFE, CSM, EPDM ... ductile iron, cast steel, stainless steel 304,316,316L according to special working condition.4.If the valve leakage after two ... years service, just remove handle then add a bushing to prevent leakage , need not disassemble the valve or change a ...